31.78% is the change from 258 to 340
Calculation steps:
[( 340 - 258 ) ÷ 258] x 100 = 31.78%
Formula
Percentage change = [(340 - 258) / 258] x 100
Subtract the new number by the original number
340 - 258 = 82
82 ÷ 258 = 0.3178294573643411
0.3178294573643411 x 100 = 31.78%